Build Thread- Datacop's JGRO Build

[datacop]

I've been a member of the zone for a few years.. wanting, drooling, wishing..

Time to stop dreaming and start doing!

First things first for me was to take care of the electronics. I've purchased the HobbyCNC 4 Axis Pro kit and assembled them. You can view the build thread for that here: http://www.cnczone.com/forums/showthread.php?t=108806

The next steps for me was to make sure that my JGRO had a home to live. So today I went and purchased the hardware and lumber to make myself a nice assembly table which will be the stand for the machine once it's done.

I built the table from the designs I posted here: http://www.cnczone.com/forums/showthread.php?t=109444

Once the raw lumber (8 2"x4"x8') was cut, assembly of the table took about 2 hours. The only variation of the plan was to double layer the top with 2 1/2" boards instead of one.. taking a queue from counter top builders in doubling their substrate.

Now that the table is built, I think I should have made the legs 30" instead of 36". But time will tell. If it turns out that the table is too tall, I can always cut it down later

The last picture is my shop foreman

[datacop]

Spent some quality time and money at Lowes and Home Depot today..

We have parts!

I got an excess of everything (except gas pipe) for when I screw something up

I'm still waiting on my order of skate bearings to arrive before I start cutting and assembly. I like to have everything together when I start a project.

Community question:

In my "day job" as a software programmer, one of the skills that I've developed is the ability to create documentation. Would the 'Zone find it beneficial if during the build of my machine, I create a "build handbook" and released it back to the community? If it's something that would help folks, I'd be glad to do it.. but if it's something that's not needed or would be considered a "waste of trees" then I won't bother.

Let me know one way or another

[guerd87]

Moving quickly! Wish we had Home Depot over here, they seem great. We have Bunnings but they either have odd sized stock or really expensive!

I like the idea of a build guide, as long as you are building it directly to the plans. I changed mine up a bit just depending on how I felt about the idea at the time. Found easier and better ways of doing things.

[gmfoster]

Build guide would be great.

[datacop]

So my order of bearings came in from http://www.vxb.com so it's time to start making some cuts.

The first thing I did was to cut the cutting surface out of 3/4" MDF (no pictures of that) then move on to the pipe support blocks (large) and end supports for the Y axis.

There is a slight misprint in the parts list for cnc_dtl01 and cnc_dtl02. The parts manifest list them as 1.5x8.25x16.25, when in actuality they are 1.5x8.25x32.5. So be aware of that as you're laying out your cuts on your stock.

For the 1.5" holes, I used a 1.5" hole saw and my drill press. Word of caution when cutting MDF with a hole saw... the fine dust gums up the teeth VERY quickly. So you need to make many shallow passes while withdrawing the bit from the MDF to clean it. I used a piece of scrap wood when the bit was up to clear the teeth.

Also, I only cut halfway through on the front side, then I flipped the board and finished the hole from the other side. This allowed me to remove the plug from the hole saw without having to take it apart to clear it.

Once I got the motor side support cut (both pieces) I glued it together and moved to the large adjustment blocks. I followed the same procedure for cutting the holes in the adjustment blocks as I did for the side supports.

I'll need to stop by Lowes tomorrow to find a "thread forming" tap, since all of mine are "thread cutting".. not quite sure what the difference is yet, but I've read enough of these build threads to seek one out

[gmfoster]

Originally Posted by datacop So my order of bearings came in from http://www.vxb.com so it's time to start making some cuts. The first thing I did was to cut the cutting surface out of 3/4" MDF (no pictures of that) then move on to the pipe support blocks (large) and end supports for the Y axis. There is a slight misprint in the parts list for cnc_dtl01 and cnc_dtl02. The parts manifest list them as 1.5x8.25x16.25, when in actuality they are 1.5x8.25x32.5. So be aware of that as you're laying out your cuts on your stock. For the 1.5" holes, I used a 1.5" hole saw and my drill press. Word of caution when cutting MDF with a hole saw... the fine dust gums up the teeth VERY quickly. So you need to make many shallow passes while withdrawing the bit from the MDF to clean it. I used a piece of scrap wood when the bit was up to clear the teeth. Also, I only cut halfway through on the front side, then I flipped the board and finished the hole from the other side. This allowed me to remove the plug from the hole saw without having to take it apart to clear it. Once I got the motor side support cut (both pieces) I glued it together and moved to the large adjustment blocks. I followed the same procedure for cutting the holes in the adjustment blocks as I did for the side supports. I'll need to stop by Lowes tomorrow to find a "thread forming" tap, since all of mine are "thread cutting".. not quite sure what the difference is yet, but I've read enough of these build threads to seek one out

This look like the HF hold saws.. I just used them today to make some wood plugs for my RV where the removable table legs go.. Don't work bad if you can get them square up.
Garry

[datacop]

The majority of my shop time today was devoted to the large adjustment blocks and the motor side support wall.

I searched all over town to find a "thread forming tap" or a "roll form tap" to no avail.. Local lumber stores, lowes, home depot.. I even went to our local Rocklear (http://www.rockler.com) and harbor freight stores... I realize I could have ordered one on-line, but patience is not my strongest suit .

so I broke out my trusty 1/4 x 20 cutting tap (first picture) and went to work and making the threads in the first adjustment block for the adjuster bolts.

The tap cut beautifully on the way down and I had convinced myself of smooth sailing. The problem came when I tried to back the tap out of the MDF. It seems that a bit of a "dust ball" for lack of a better term had gotten lodged in the back side of the flutes. When the tap tried to roll over this dust ball, it caused the MDF to split right down the center. (picture two).

After some trial and error, I found that if I secured the adjustment block in my bench vice and kept it at a "snug" fit (picture three), that I could tap the side holes without any sort of drama. Picture four shows a test fit of the freshly cut threads.

Once all the side threads were cut, I used a bit of Locktite Super Glue on the threads to stiffen them up. It's important to note that if you do use the super glue trick, that you will have to re-tap the holes to clean them back up. Having said that, make sure that the glue is dry before you go to re-tap, the glue and MDF dust will wreak havoc on your tap's cutters and flutes.

When the adjustment blocks were done, it came time to attach them to the side supports. Instead of actually measuring for the holes in the side supports to tap for the machine screws... I simply clamped an adjustment block over the pipe through hole in the side support, lined everything up, then used the drill press to drill out the pilot holes (picture six).

Once I had the holes drilled, I switched to my #10 24 tap and threaded the holes in the side supports (picture seven). After they were tapped, I used the same super glue reinforcement technique as I did with the adjustment blocks.

And with that, a little final assembly work.. and this is where we're at now (picture eight / nine)

Tune in tomorrow, same bat time, same bat channel

[datacop]

My shop crew and I decided to dive head long into the machine build today, knocking out the machine base support.

I have to be totally honest, building the base support is the most un-fun we've had in building this machine thus far.

If someone could give us a pointer or short cut to make building the bed support a little more enjoyable (read: easier) I'd be very open to suggestions.

[datacop]

For the cutting bed support assembly, I decided to take a slightly different approach. After looking at the plans, I noticed that there were three "ladders" with ribs spaced out starting at 7.5" apart.

So my thought was to build the subassembly in stages, then glue the pieces together. The first picture shows my 7.5" spacer I used to space the ribs and the second picture is the sub-subassembly's drying. Once the three ladders were dry, I could use my 7" spacer to place the ribs and glue the ladders together.

After the torsion frame was built, I glued it to the skin, then glued the whole thing to the cutting surface that I made on day one. I used a piece of laminated wood and a pair of 35lb dumb bells to weight the whole thing down as it dried.

After the cutting surface assembly was complete, it was just a simple matter to attach the end supports to the base support torsion box. A pair of 2.5" furniture bolts per side that I had laying around did the job nicely. There are no measurements in the plans for where to place the bolts (that I found), so I placed the bolts 9" off the centerline on each side, and 1.5" up from the base.

For grins and giggles so that I can see some "real" progress, I put the cutting surface on the end supports.. it fits incredibly snug! So much so I pinched my fingers putting it on. Then I slipped in the Y axis pipes for that "finished" look

What do you think?

[datacop]

Not much "obvious" progress today. I rough cut all of the pieces for the gantry and spent the day making the small adjustment blocks. For being little 2"x2" parts, there's a heck of a lot of machining that is involved with them

I did manage as well to get the right side gantry wall measured, drilled and adjustment blocks put on as well.

All in all, can't complain

[datacop]

Question about Flanged Bearings...

The parts manifest call for 5x flanged bearings.. but it doesn't give any hint as to which ones to buy. I looked on the McMaster site that the manifest points to and I'm not even more confused than before.

I realize that the JGRO plans are 6 years old now (a true testimony to his original design!) and things may not be available anymore..

I've got more than enough skate bearings to come up with my own design for them.. should I investigate that route or find a purchased item somewhere.. if purchased.. what one?

----------------
Edit:

Never mind.. after reviewing the plans a bit further and examining the exploded detail views.. I've got a better understand of what's needed. I placed an order with VXB for the flanged bearings since VXB can get them to me in 2-4 days, where McMaster would take "within 2 weeks"

[datacop]

With the heat index of over 100 degrees outside, working in the garage has been a bit.. unbearable. However, tonight I took advantage of the night time temps and got a bit more work done.

I finished up the other side gantry support, and cut out the rear gantry brace on the scroll saw. The interesting part of the evening came when I realized I had to drill and tap the ends of the rear gantry support.

My drill press is just a small bench top press, so I couldn't drill the holes with that. That of course means having to do it with a hand drill. I remembered a tip that I learned as a kid for drilling "pretty darn good and straight holes" with a hand drill...

First I secured the back support in the bench vice and made sure that it was level. Once the work piece was secured, I put the small level on the top of my drill. This allowed me to make sure that the drill was level with the work piece, and I could "eyeball" the bit to be square "side to side" going in.

Once all of the holes were drilled and tapped, I used CA on the threads and re-tapped them to clean up. Assembly was a snap after that.